This invention relates to magnetic tape cartridges suitable for use with magnetic recording and reproducing apparatus, and more particularly, to a locking device for a cover of a magnetic tape cartridge for locking the cover of the magnetic tape cartridge when it is in a closed position to prevent it from inadvertently opening.
To facilitate handling of magnetic tapes, magnetic image recording and reproducing apparatus for recording and reproducing image output signals and television signals of video cameras use magnetic tape cartridges each of which have a magenetic tape contained in a cartridge case to enable recording and playback of the signals to be performed continuously by successively replacing the magnetic tape cartridge by a new one. The magnetic tape cartridge containing a magnetic tape comprises a supply reel and a takeup reel, the supply reel having the magnetic tape wound the thereon. When the magnetic tape cartridge is loaded on a magnetic recording and reproducing apparatus and the apparatus is brought to a recording mode or a playback mode, the supply reel and the takeup reel are driven so that the magnetic tape is payed out of the supply reel and wound on the takeup reel.
As disclosed in U.S. Pat. No. 4,173,319, for example, a magnetic tape cartridge is formed at a front surface of a cartridge case with open areas for withdrawing the magnetic tape from the cartridge case when recording or playback is performed. Thus, a portion of the magnetic tape is exposed on the front surface side of the cartridge case at all times, and dust might adhere to the exposed portion of the tape or the hand of an operator might be brought into direct contact therewith. To avoid this trouble, a pivotable cover is pivotably connected to the front surface of the cartridge case.
When the magnetic tape cartridge is not in use, the pivotable cover is in a closed position to cover the portion of the magnetic tape which is exposed on the front surface side of the cartridge case when the tape cartridge is used for recording or playback. The pivotable cover is kept in the closed position by locking means. When the magnetic tape cartridge is loaded on a recording and reproducing apparatus, unlocking means provided to the recording and reproducing apparatus releases the locking means for the pivotable cover to allow the cover to move in pivotal movement from the closed position to an open position, so that the magnetic tape can be withdrawn from the cartridge case for a predetermined length and wound on a recording and reproducing head to perform recording or playback.
The locking means of the cartridge case comprises a locking claw located on one side of the cartridge case near the pivotable cover and brought at its forward end into engagement with a recess formed on an inner surface of the cover when the cover is in the closed position, to thereby prevent the cover from being brought to an open position. A pin integrally formed with the claw and projecting from the side of the cartridge case is located near the claw and, when the cartridge case is loaded on a magnetic recording and reproducing apparatus, an unlocking pin presses against the pin of the cartridge case to force same into the cartridge case and moves the claw integral with the pin rearwardly into the cartridge case, to thereby release the claw from engagement with the cover and allow the cover to move to the open position. The claw and the pin of the cartridge case are biased in one direction by a spring, so that they are normally urged by the biasing force of the spring to protrude away from the side of the cartridge case.
In the magnetic tape cartridge of the prior art, the claw and the pin extend outwardly from the cartridge case at one side and it is necessary, when it is desired to unlock the cover, to press the pin into the cartridge case at the side thereof. This would place limitations on the process for loading the magnetic tape cartridge on a magnetic recording and reproducing apparatus. More specifically, when it is desired to unlock the cover, it is necessary to move the claw which is in engagement with the recess of the cover back into the cartridge case. To this end, the unlocking pin should press against the pin extending from the cartridge case at one side thereof, and it is necessary either to move the unlocking pin or attach the cartridge case to the recording and reproducing apparatus in such a manner that the pin of the cartridge case is pressed by the unlocking pin.
The magnetic recording and reproducing apparatus is provided with a number of pins including a reference pin for placing the magnetic tape cartridge in a correct position, a sensing pin for sensing erasure prevention, a brake releasing pin for releasing the takeup and supply reels from the braked condition, etc. These pins are preferably fixed and remain stationary to minimize misoperations. Likewise, the unlocking pin for unlocking the cover allowing same to move to the open position, is preferably fixed and remains stationary. A magnetic recording and reproducing apparatus preferably allows a magnetic tape cartridge to be loaded thereon from any direction as desired. Stated differently, it is preferable that the magnetic tape cartridge be automatically placed in a correct position in the magnetic recording and reproducing apparatus and the cover of the cartridge case be unlocked when the magnetic tape cartridge is loaded on the magnetic recording and reproducing apparatus irrespective of the fact that the cartridge case may be inserted in the apparatus through its top side, through its front side or through its lateral side.
This invention has as its object the provision of a locking device or a cover of a magnetic tape cartridge which enables the cover to be unlocked automatically when the magnetic tape cartridge is loaded on a magnetic recording and reproducing apparatus no matter from which direction the magnetic tape cartridge may be inserted in the magnetic recording and reproducing apparatus.
The locking device for a cover of a magnetic tape cartridge according to the invention comprises a projection formed on one of a plurality of arms for supporting a pivotable cover and engageable with an engaging claw section of a locking member pivotally connected to a magnetic tape cartridge case. The locking member further comprises a resilient section for urging by its biasing force the engaging claw section into engagement with the projection of the arm, and an operation section located in a position in which it is capable of cooperating with an unlocking pin which may move from one of three different directions whereby latitude can be imparted to the loading of the magnetic tape cartridge on a magnetic recording and reproducing apparatus.